In the Shadow of the Oval Office offers a timely retrospective on the role of national security adviser through 50 tumultuous years. The post is something of an anomaly: although originally created as a pure staff position and exempt from the requirement of Senate confirmation, under some presidents the national security adviser has eclipsed the constitutionally mandated cabinet officers to become, next to the president, the most powerful force in U.S. foreign policy. Commentators and policymakers frequently deplore the often intense rivalries between national security advisers and secretaries, yet the rivalries emerge over and over again. Daalder and Destler provide examples, such as the George H. W. Bush administration, in which the system worked well; they point to others, such as the Reagan administration, in which failures by the adviser left the president exposed to damaging political and policy failures. In recent years, a third force has begun to appear in the executive branch; a series of powerful vice presidents, including Al Gore, Dick Cheney, and now Joe Biden, have emerged, with varying results, as partners and, occasionally, rivals to both the secretary of state and the national security adviser. Overall, the growth in the complexity of the foreign policy machinery appears to reflect the continuing rise in the importance of foreign policy for U.S. presidents. The world is so large, its problems so complex, and the constitutional role of the president in foreign policy so powerful, that presidents have over time seemed inexorably driven to expand the group of powerful aides who help shape foreign policy. Coordination among these usually strong-willed, self-confident, and brilliant aides poses problems of its own; building an appropriate system and managing the inevitable rivalries is one of the key challenges facing a new president.